Complex relationships between stream functions and naturally stochastic processes make evaluation of stream modification projects difficult. Informed by vague objectives and little monitoring data, project evaluations can often be a subjective attribution of success or failure. Given that channel form is closely related to stream function, this research provides a framework to rapidly assess current conditions as a continuum of damage to channel functioning. The damage states focus on damage to hydraulic and geomorphic parameters that describe basic stream functioning and support higher level functions including managing water quality and supporting various life cycles. Based on widely accepted evaluations of physical habitat quality and stream stability, the damage states describe a continuum of damage in multiple categories related to the stream functions that are affected by the modification design. The highest level of damage in the damage categories provides an overall assessment of project conditions and the individual scores in the damage categories can be used to calculate relative vulnerability and relative risk associated with the stream modification project. Relative risk is determined using a vulnerability-criticality risk logic matrix which provides a category of recommended action based on project conditions and potential impacts. The damage states provide an objective characterization of post-construction project performance and the risk assessment provides guidance for allocating resources to project maintenance or rehabilitation. These tools can be used to improve the results of stream modification and protect environmental resources and physical assets.